This is the second of two lessons focusing on polynomial identities. In the previous lesson, students learned what identities are and in this lesson students practice determining when an equation is an identity.
The warmup is meant to help students make sense of the following activity (MP1), where they investigate an identity that can generate Pythagorean Triples. This lesson includes an optional activity to use if students need additional practice proving algebraically that an equation is an identity. In the last activity, students prove identities involving rational equations as they learn about Egyptian fractions and consider different ways to rewrite a fraction as the sum of unit fractions.
Lesson overview
 24.1 Warmup: Revisiting an Old Theorem (5 minutes)
 24.2 Activity: Theorems and Identities (10 minutes)
 24.3 Optional Activity: Identifying Identities (15 minutes)

24.4 Activity: Egyptian Fractions (20 minutes)
 Includes "Are you Ready for More?" extension problem
 Lesson Synthesis
 24.5 Cooldown: A Cubic Identification (5 minutes)
Learning goals:
 Create expressions to represent a mathematical situation and justify an identity about them.
 Justify (in writing) general relationships by using identities.
Learning goals (student facing):
 Let’s explore some other identities.
Learning targets (student facing):
 I can justify why identities are true.
Standards:
 This lesson builds on the standard: CCSS.HSAAPR.C.4MS.AAPR.4
 This lesson builds towards the standard: CCSS.HSAAPR.C.4MS.AAPR.4
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